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MG Midget and Sprite Technical - Which Gasket Sealer? (if any...)

Hi, all.

I broke a halfshaft recently (first ever), and once the new diff gasket gets here I'll reassemble everything with a new (used, actually) axle.

What's your collective opinion on gasket treatments when doing such rebuilds? Or do you use any at all?

As for the break itself, it occurred while on my way to our annual All-British Car Show in St. Louis County. A couple miles from home I noticed I was coasting in all gears. There was no "bang" or anything, just a cessation of drive. I coasted into a parking lot, and had the car brought home later on a flatbed.

The broken axle was a major pig to remove, as it had jammed in the sleeve just outboard of the gear spline, thanks to fragments. I finally got the thing out using a hub-puller slide hammer combo. Apart from some minor scarring inside that sleeve, the diff looks okay... no damage to the spline at all, and the broken stub came out easily enough. I've cleaned out all the "glitter", and it's ready to go back together. Lee Fox, if you're reading this - thanks again for the spare axle. Marque of Friendship, and all that. ;-)


Gryf Ketcherside

Second pic... dead though it may be, it still looked awfully pretty up there on the truck.

This was the first time in 23 years of ownership that I've missed the show due to mechanical problems.


Gryf Ketcherside

My stance is simple. There should be no need for gasket gunk anywhere on the car :-)

Shame about the breakage. Was there any play in your rear hubs that you know of? How were the bearings?

Malcolm Le Chevalier

Malc -

Then there shall be no gunk. Thanks! The hubs and bearings are fine. I had replaced the bearings several years ago, and they're still good.

Gryf Ketcherside

Whereas I use gasket sealant on everything bar the cylinder head! I used to use Hylomar but now use Locktite copper coloured stuff.

I remember years ago my 18 year old mate telling his mum that there was no need to use gasket sealant while he was refitting his rocker cover. After all, he pointed out, Rolls Royce didn't use any on their cars due to the superior tolerances. His mum paused and then rather sagely said 'Yes but this is a Morris Marina'.

John Payne

... Hylomar was developed FOR Rolls Royce ...
Chris at Octarine Services

Hylomar for me too. I have never been that successful with dry gaskets. If it leaks on the rear axle its new shoes as well!!
Bob Beaumont

I stopped using Hylomar when I found a load of it stuck to the sump oil strainer, it must have broken away from the edges of the gasket after squeezing out. The stuff I use now doesn’t do that. I probably had been using too much Hylomar though.

Come to think of it Chris, I think the Hylomar I used to get was supposed to be used on our Rolls Royce jet engines but somehow quite a few tubes ended up in my toolbox!
John Payne

Not a Hylomar fan at all
If I need something sealed I use VHT coppercote spray--magic(used sparingly) on metal headgaskets as well
William Revit

I buy Hylomar in cartridges - with the smallest of holes in the nozzle - a thin "worm" of sealant on the gasket, smeared out with my finger is all that is needed.

No more than that or it will get squeezed out - I once rebuilt an overdrive for a customer while he waited & watched - then he went away and fitted it with so much Hylomar that the whole inside of the unit and the gearbox was coated in little bits of it. Needless to say the whole box turned up later for me to fix it!
Chris at Octarine Services

For many years I used to put a smear of grease on both sides of a paper gasket. I don't now recall where I got that idea from but I guess some old gadgee must have told me. I don't know if it helped or hindered, it's just what I did!

I suppose it acted as a position holder if nothing else. And it does make removal of the old gasket easier when it has to be removed for the leaking joint to be re-done !

both my Uncles use whatever gloss paint they have kicking about !
haven't followed in their footsteps myself, but just thought i would add a comment
P Bentley


I still use grease on cork and paper gaskets, may have known the same old gadgee. Now I'm an old gadgee, and I tell every young mechanic I know to do the same ;-)



My dad told me the grease method umpteen years ago. I think its mentioned in early workshop manuals when refitting rocker box gaskets.
Bob Beaumont

Indeed Lazza, becoming an old Gadgee entitles one to advise all sorts of mystical solutions that modern science hasn't a hope of competing with!

Only yesterday I used Hylotyte Red 100 as it had previously worked well with a coolant weep where Universal blue had failed.

John Twist in his B o/d video at least recommends grease on the filter.

As Malc has put perhaps you sholdn't need a sealant in addition but in the world of used, abused and piss-poorly made parts there seems to be a place.
Nigel Atkins

Great word Gadgee, I always thought it was from India or somewhere like that and perhaps a bit dodgy. We use it a lot in the RAF.

But it turns out it’s from the north of England:

By the way Guy, totally off topic but I dropped my set of wheels off for blasting and powder coating yesterday. I’ll let you know how they turn out!
John Payne

John looking at definition number two your idea of prejudice might not be that far off.
Nigel Atkins

Yep, a Gadgee is Cumbrian for an old person (well, I know it from my Cumbrian wife anyway!)
Malcolm Le Chevalier

I picked it up when living in Northumberland so that last definition fits. But it's an old man, so definitely wouldn't be used for a woman (a sexist definition by today's pc world) and I always thought it related to a revered and sage individual full of snippets of wisdom. Lazza and I now qualify!

Old is relative though, to someone in their early 20s others in their 30s are old, those in their 50s and 60s very old and those older oxygen thieves.
Nigel Atkins

True Nigel, and I suppose for that reason age is a pretty consistent thing, not linear as some scientists might believe.

Brian, who runs the local scrapyard has always been old. I have known him for 40 years, and in my mind he hasn't aged much at all in that time. He still turns up at the yard, 7 days a week. He is now, by my reckoning, 84. So he was just as old at 44, and looked much the same. He is a Gadgee.

I recently started using Dow Corning 732 RTV. Seems to be much higher quality than the Permatex RTV you buy at the autoparts store. On the rear axles, I'd use a new oring and a the 732 without the paper gasket.
Trevor Jessie

As Malc said - no gasket goo anywhere near the axle. But I'll often drwess the metal surfaces with a file and/or fine emery cloth or wet & dry.
David Smith

I am a firm believe in 3 types of joins.

No sealant
HG or other crushable gaskets

Wellseal (the original “developed by RR” for the merlin, not for turbines like hylomar)
On any gasket between machined surfaces with the original gasket.
Oil filter housing, waterpump etc

Any good silicone
On all joints between machined and pressed steel surfaces with the original gasket.
Like sump and timing cover.
Since a 40 year old piece of pressed steel is never ever perfectly flat.

I'm glad you put that I was trying to think of Wellseal but had forgotten it (and probably will again).
Nigel Atkins

On the subject of gaskets, am about to drop the sump and fit new gaskets. I use grease on the side gaskets, but the front and end gaskets I've purchased are rubber (whatever happened to the strips of cork!). Do I fit the rubber ones dry? I can't see grease being very helpful - or is it??
Geoff Mears

I was told to use grease when fitting the silicone rocker cover gasket though I couldn't see that it really helped, or hindered.

Normally it's the rear seal TAM1089 that is rubber and the front seal LZB10005 that is cork. The cork seals sometimes need trimming to fit and personally I dislike that as I'm never sure if I've trimmed too little or too much.

In the sets of sump gaskets you can often get two straight cork gaskets, I think I gave 8 away last year's NEC.

LZB10005 -

TAM1089 -
Nigel Atkins

Geoff, if you don't already know this, before refitting the sump check along the mating flange with a straight edge. You almost always find the metal raised up into shallow 'volcanoes' around each screw hole. Carefully dress these back down with a ball pein hammer.

If anything, it's better that they deform downwards rather than be raised up as they will then pull back tight against the sump as you tighten the sump bolts.

Geoff - fit the black rubber ones dry, they will stay in place better during assembly and tightening.
David Smith

Thanks all for your input. I'll fit them dry as per David's suggestion, and check the mating flange edges.
Geoff Mears

Age - depends how you look at it, it could be considered exponential:

When you are 1 another year is doubling your age

When you are 50 another year is only 1/50th


This thread was discussed between 11/10/2018 and 16/10/2018

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